This invention relates to devices for shoring open excavations. The device includes a pair of shoring panels held vertically apart and parallel to each other against sidewalls of excavation by a pair of strutting assemblies. Each shoring panel has laterally, on either end a vertical guide, and lengthwise two identical cutting edges of triangular cross section. The cutting edges are inversely arranged one on the top and the other at the bottom of the panel and opposite relative to sidewall of excavation. The panel is therefore versatile by mean that it could be used all ways, the inside out or upside down. Each strutting assembly has a pair of vertical struts held against each other by at least one horizontal strut that is fastened by pin or bolts onto vertical struts. Each vertical strut is provided lengthwise with a panel guide cooperatively engaging the guide of shoring panel and interlocking with it, so that shoring panels slide independently from each other, while the strutting assembly can adjust different pipe culverts. In another perspective, the panel is versatile in the sense that it could be used as a traditional trench shield, as a sliding system in combination with the strutting assembly and/or with any other sliding shoring device provided with panel guide that fits the guide of shoring panel.
The components of this shoring device are assembled together during first stage of excavation, up to 4 ft. deep, and create altogether a two side wall box. Afterward, the panels are pushed down one at time and independently to each other as excavation progresses. If depth of excavation is superior to height of the panel, another such shoring device is stacked above the previous one. The removal from the ground of such shoring device is easier consisting of simply removing the strutting assemblies first and the panels afterward.
There are many shoring devices used for securing the walls of open excavations and the working space inside it. One type of such shoring devices, commonly called trench shields, have usually two panels held by individual spreaders pinned or bolted onto the extremities of each panel via flanges or fixed connectors. The panels are usually provided with a cutting edge at the bottom part to facilitate penetration into the ground. The majority of these devices are rigid in a sense that they do not allow relative movement between spreaders and panels and most of the time their installation is achieved after excavation.
Other types of shoring devices having panels and sliding spreaders are disclosed in U.S. Pat. No. 3,530,679 (Krings), and U.S. Pat. No. 5,503,504 (Hess et al.). The panels used by these devices comprise support columns or special legs fastened temporarily or permanently onto the side of the panel, which is inner relative to interior of the trench. Individual spreaders or a strutting frame slide formlockingly between respective opposite columns of a pair of panels. For any of these devices, the panel is designated to work with a defined type of spreader system and in a very unique way. The bottom and upper part of the panel are not technically substitutable, likewise the side of the panel which is inner relative to interior of the trench can not be outer and vice—versa. The columns or legs fastened onto inner side of the panel increase drastically the volume in transportation or the storage of such panels. A very important limiting aspect of mentioned devices is the fact that their panels are not, or could not be used with other existing types of shoring devices requesting additional inventory in panel. Other difficulties related to staking of two or more of these devices, have revealed limitations regarding successive alignment of the columns and/or spreader system.
Another type of shoring device, commonly called slide rail shoring system, has a plurality of pairs of opposite rails or supporting columns spaced along the trench so that each pair is supported by a strutting frame which slides within opposite rail supports. Each rail support is provided on either side with guide channels where edges of large shoring panels slide within so that every two adjacent rails are connected with at least one shoring panel. This type of shoring device is currently used in the construction projects despite aversion in costs, weight and structural damages during utilization.
Knowing shoring device that has panels sliding vertically within excavation without using vertical support columns is disclosed in U.S. Pat. No. 6,224,296 (Fukumori). This device uses two pairs of large shoring panels. The first pair of panels, which shores the upper part of trench pressing against the excavation walls, is fixed at ground level. The second pair of panels slides within first pair shoring thereby the lower part of excavation. Both pairs of panels are connected and use sets of rigging to control the installation and removal of this device. Such device perform poorly in deep excavation and requires accurate installation regarding the space between first pair of panels their parallelism, etc. The removal of the panel is also associated with damages of guiding pair of panels.
U.S. Pat. Nos. 3,621,660, 3,910,053 and 4,657,442 (Krings), U.S. Pat. No. 5,310,289 (Hess), U.S. Pat. No. 6,164,874 (May) disclose various slide rail shoring system, all of them including multiple pairs of columns, spreader systems and large shoring panels. The support columns and the spreader systems used with these shoring systems are very heavy and are often hammered to push it down which often results with strong damages and heavy costs in maintenance.